Roll and method of manufacturing rolls



Oct. 22, 1935. F. c. BIGGERT. JR.. ET AL 2,018,247

ROLL AND METHOD OF MANUFACTURING ROLLS Filed June 11, 1935 2 Sheets-Sheet 1 FIG. 1. 6

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6 k FIG. a F1627 a 62 1; 3; 4? 5- 21 Y M. INVENTORJ v ATTORNEYS Oct. 22, 1935. F. c. BIGGERT. JR.. ET AL 2,018,247

ROLL AND METHOD OF MANUFACTURING ROLLS Filed June 11. 1955 2 Sheets-Sheet 2 FIG. 6. 5

FIG. .9. '2; V FIG. 10.

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29' INVENTORJ MC, (WITNZSSES W 2 7/% ATTORNEYJ Patented Oct. 22, 1935 UNITED STATES PATENT OFFICE ROLL AND METHOD or MANUFACTURING nous Florence C. Bigger-t, Jr., Grafton, and Henry Mueller, Pittsburgh, Pa., assignors to United Engineering & Foundry Company, Pittsburgh, Pa., a corporation of Pennsylvania Application June 11, 1935, Serial No. 25,974

18 Claims.

ing-up rolls for 4-high mills, of the kind comprising a harder shell or sleeve forming the work ing surface of the roll which is fitted by a shrink fit onto a central supporting shaft or arbor, and is a continuation in part of the invention disclosed in application Serial No. 750,824 for Roll for rolling metals filed by the present inventors October 31, 1934.

An object of the invention is to provide a roll of this character which is economical to manufacture and which is so designed as to prevent any relative movement of the sleeve with respect to the arbor. I

Another object is to provide an improved builtup roll having in addition to the advantages of built-up rolls as heretofore constructed all of the advantages of a solid cast roll without the disadvantages or faults of either.

A further object is to provide an improvement in the method of manufacturing rolls of this character.

These and various other objects, as well as thevarious other novel features and advantages of the invention will become apparent when the following detailed description is read in conjunction with the accompanying drawings of which Fig. 1 is an elevational view of a roll constructed in accordance with the invention; Fig. 2 a longitudinal section taken through the roll shown in Fig. 1; Figs. 3 and 4 longitudinal sectional views respectively of the sleeve and arbor comprising the roll shown in Fig. 2 before-they are assembled; Fig. 5 a view similar to Fig. 2 of a modified form of the invention; Figs. 6 and 7 views similar to Figs. 3 'and 4, respectively, of the sleeve and arbor shown in Fig. 5; Fig. 8 a view similar to Fig. 2 of another modification of the invention; Figs. 9 and 10 longitudinal sectional views respectively of the sleeve and arbor comprising the roll shown in Fig. 8, before they are assembled; Fig. 11 a view also similar to Fig. 2 of still another modification of the invention and Figs. 12 and 13 longitudinal sectional views respectively of the sleeve and arbor of the roll shown in Fig. 11 before they are assembled.

As illustrated in the drawings a roll of the type contemplated by this invention comprises essentially a centrally disposed supporting shaft or arbor I and a cylindrical sleeve or shell 2 made of material harder than that of the arbor and which is fitted on the arbor by means of a shrink flt and forms the working surface of the roll. The chief purpose of making rolls of this character is to provide them with a harder and more durable working surface than it is possible to obtain where they are cast in a single piece and to also eliminate the warping and internal streses encountered in the latter type of roll. By making the outer or working portion of the rolls in a separate piece and in the form of a shell, it can be more effectively heat treated than a solid roll, 10

and if desired it may be made of a harder steel or alloy than the arbor which is not subjected. to the same stress in service as the working sur-' ace.

this type the most difficult is that of preventing the shell 2 from creeping about or moving axially on the arbor I and which, if permitted, renders thelrolls unfit for service. To overcome these difficulties in accordance with this invention, referring to Figs. 2, 3 and 4, the shell Zis provided with a uniform internal bore and the arbor I with three cylindrical sections 3, 4 and 5, all of which have a diameter before assembly in excess of the bore of the shell. The smaller of these sections 3 and 5 are located at the ends of the roll and provided with a diameter which, when the shell is shrunk on it, provides a unit tensile stress in the shell preferably of between 10,000 to 18,000

Among the problems encountered in rolls of 15 pounds per square inch and corresponding to that 30 customarily provided in such rolls, a tension of 16,000 pounds per square inch being recommended. These values will, of course, vary depending upon the properties of the metal used and may considerably exceed those referred to. The central section 4, however, is provided with a diameter which is sufliclently greater than that of the end sections 3 and 5 as to provide a unit tension in the shell over such portion of the roll which is in the neighborhood of twice the unit 40 In addition by reason of its larger diameter and the greater unit tension developed by it between the arbor and shell, this enlarged central section 4 of the arbor, as shown in Fig. 2, distorts the inner portion of the shell 2 in such a way as to form locking shoulders 6 and I in the shell which positively prevent it from moving endwise on the arbor.

To more definitely and positively insure against any axial displacement of the shell 2a on the like parts are distinguished from those in Figs.

2, 3 and 4.by the addition of the sufllx a, the arbor la may be provided with a reduced diameter in its central section la, and the shell also with a correspondingly reduced section 2b to provide the assembly with more definite and positive looking shoulders 6a and la for preventing the shell from moving endwise along the arbor. The relative diameters of these sections, as will-be appreciated in keeping with the invention, are made the same as the corresponding sections in the previously described roll so as to positively prevent any creeping of the shell, and the differences in diameter will be of course within the shrinking limits for assembly.

Another way of practicing the invention, as 11- lustrated in Figs. 8 to 10, inclusive, is to shrink a shell I; having a. uniform bore onto an arbor lb which is provided with a barrel-like convexity over the portion In thereof to which the shell is secured. A still further way, as illustrated in Figs. 11 to .13, inclusive, is to provide the arbor with a uniforn'f'diameter 'over its shell-engaging portion and to shrink thereon a shell having a bore which decreases in diameter along an are from its two ends to its center. The relative diameters of the shell bores and arbors in these latter modifications of the invention are of course proportioned in the same fashion as those previously described to provide the necessary fit between such parts to prevent both creeping and axial displacement of the shells as well as enhance the life of the resulting rolls. An advantage of this construction is the parts are easier to make, and, especially the former, in which the arbor is made with a convexity, as such can be obtained by a simple cutting or grinding operation.

As will be appreciated also by those skilled in the art, the ratio of the areas of the arbor over the portions of different diameters may be varied, as may the tensions due to shrinkage, depending upon the type and characteristics of the metals comprising the shell and arbor and the type of service to which the rolls are to be subjected. It will also be understood that the disposition of the area or areas placed under the greater unit pressure and the arrangement thereof along the length of the roll may be also varied somewhat without departing from the spirit of the invention, and such is so contemplated by the appended claims.

To facilitate the assembly of the arbor in the shell when the roll is being fabricated, an integral or separately attached collar 8 may be provided at one end of the arbor for determining when the arbor is properly centered in the shell and which when the shell is hot will be when the collar is resting against the end of the shell, the collar being so located as to allow for endwise shrinkage of the shell in determining the location of the cooled shell on the'arbor. After the shell is in place the collar 8 of course may be removed if desired to provide a symmetrical roll.

In making a roll according to this invention the exterior of the arbor and the interior of the roll are first machined to the proper dimensions. The shell is then uniformly heated in any suitable fashion until it has been expanded sufiiciently to receive the arbor. When in such condition the end of the arbor opposite the collar 8 is inserted in the shell and projected through it until the collar it rests against the adjacent end of theshell. placing the shell-on end and lowering the arbor by means of a crane into the shell. After the arbor is in place and the shell has cooled the exterior of the roll is finished and polished, there-.- by removing any distortions developed by the 10 fitting of the shell on the arbor and rendering the roll ready for use.

Among the advantages of this invention is the provision of a built-up roll which is relatively simple to manufacture and assemble and one 15 which has substantially the same characteristics of rigidity as a solid cast roll.

According to the provisions of the patent statutes, we have explained the principle and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and 25 described.

We claim:

1. Roll for rolling metal comprising an arbor having a shell fitted thereon by a shrink fit and characterized by the shell-e gaging the arbor so over substantially the entir' length of the shell and the two parts being so constructed as to provide a unit tension between them over a portion of their length intermediate the ends of the shell which is considerably in excess of the unittension provided between them over the remaining opposed portions of their lengths.

2. A roll for rolling metal sheets comprising an arbor having a hollow shell rigidly fitted thereon by a shrink fit and characterized by the shell 0 being harder than the arbor and engaging the arbor over substantially the entire length of the shell and the two parts being so constructed as to normally provide a unit pressure between them over a portion of their centrally opposed areas 5 which is considerably in excess of the pressure provided between them over their opposed adjacent end portions.

3. A roll for rolling metal sheets comprising an arbor having a hollow shell fitted thereon by a shrink fit and characterized by the shell being harder than the arbor and engaging the arbor over substantially the entire length of the shell and being provided before assembly with a uniform cylindrical bore while the arbor is provided with cylindrical sections of one diameter opposite the ends of the shell and a cylindrical section of agreater diameter intermediate said end sections.

4. A roll for rolling metal sheets comprising an arbor having a hollow shell fitted thereon by a shrink fit and characterized by the shell being harder than the arbor and engaging the arbor over substantially the entire length of the shell with a tension in its central portion of between 25,000 and 40,000 pounds per square inch and a tension in its end portions of between 10,000 and 20,000 pounds per square inch.

5. A roll for rolling metal sheets comprising an arbor having a hollow shell fitted thereon by a shrink lit and characterized by the center portion of the shell and arbor being provided with a normal tension of substantially 33,000 pounds per square inch and the end portion with a. normal This preferably is accomplished by 5 tension of substantially 16,000 pounds per square inch.

6. A roll for rolling metal sheets comprising an arbor having a hollow shell fitted thereon by a shrink fit and characterized by the shell having a uniform cylindrical bore adjacent its two ends and a bore of a different diameter in its central section and the arbor having exterior cylindrical end sections of a common diameter engaging the cooperating sections of the shell and a central cylindrical section of a different diameter engaging the central section of the shell, said engaging sections being so proportioned that the unit pressure betweenthe central portions of the arbor and shell is substantially twice that between the end portions.

7. The method of making a rolling mill roll which comprises securing a hollow shell upon a supporting arbor by a shrink fit in which the pressure between the shell and arbor due to the shrink fit is sufiicient to prevent relative movement thereof in service and which is less at the ends of the shell than it is between its ends.

'8. The method of making a rolling mill roll which comprises securing a hollow shell to a supporting arbor by a shrink fit in which the pressure between the shell and arbor due to the shrink fit is sufiicient to prevent relative movement thereof in service and which decreases from the center of the roll towards its ends.

9. The method of making a rolling mill roll which comprises securing a hollow shell to a supporting arbor by a shrink fit in which the pressure due to the shrinking of the shell upon the arbor is sufilcient intermediate the ends of the shell to prevent relative movement of the shell on the arbor in service and sufiiciently less at the elndls of the shell to prevent fracturing of the s e l.

10. The method of making a rolling mill roll which comprises securing to a supporting arbor by a shrink fit a hollow shell made of a harder material than the arbor and with a pressure due to the shrink fit which is sufficient between the ends of the shell to prevent relative movement of the shell on the arbor and which is sufilciently' less at the ends of the shell to prevent it from fracturing.

11. The method of making a rolling mill roll which comprises securing upon a supporting arbor having a diameter intermediate its ends which is greater than at its ends, a hollow shell of uniform interior diameter by a shrink fit due to which the pressure in the shell is sufllciently great over the enlarged portions of the arbor to prevent any relative movement between the arbor and shell in. ca but which is sufficiently less at its end por ions to prevent cracking of the shell due to the great strains in the central partof the shell.

12. The method of making a rolling mill roll,

which comprises securing a hollow shell upon a supporting arbor by a shrink fit in which the pressure in the shell due to its being shrunk upon the arbor varies from 10,000 pounds per square inch at its ends to 36,000 pounds per square inch 5 at its center.

13. The method of making a rolling mill roll which comprises securing a hollow shell upon a supporting arbor by a shrink fit in which the unit pressure set up in the shell due to its being shrunk onto the arbor is substantially half at its ends what it is intermediate its ends.

14. A roll for rolling metal sheets comprising an arbor having a hollow shell fitted thereon by a shrink fit and characterized by the shell being harder than the arbor and engaging the arbor over substantially the entire length of the shell with a tension in its central portion of between 20,000 to 36,000 pounds per square inch and a tension in its end portions of between 10,000 to 18,000 pounds per square inch.

15. The method of making a rolling mill roll which comprises providing a shell having a uniform bore and an arbor having a center portion which is larger than its adjacent portions and shrinking said shell upon said arbor to produce a considerably tighter fit between the shell and arbor in the center portions thereof than at their end portions.

16. The method of making a rolling mill roll out of a hollow shell and an arbor which comprises providing said shell and arbor with overall dimensions which require an expansion of one or a contraction of the other to effect their assembly and which are so proportioned that when they are assembled they are provided with a considerably tighter fit in their center portions than at their end portions and so assembling them.

17. A roll for rolling metal, comprising an arbor having a hollow shell fitted thereon by a 4 shrink fit and characterized by the shell having a uniform cylindrical bore before assembly and the arbor a shell-engaging portion which in-- creases in diameter from its two ends to its center. and said engaging parts being so proportioned that the unit pressure between them increases from the ends thereof toward the center and is substantially double at the center what it is at the ends of the shell.

18. A roll for rolling metal, comprising an arbor having a hollow shell fitted thereon by a shrink fit and characterized by the contacting surfaces of said shell and arbor before assembly being such as to provide a unit pressure between the shell and arbor which is substantially twice at the center what it is at the ends of the shell and which decreases uniformly from the center of the shell to its ends.

FLORENCE c. BIGGER'I, JR. 5 HENRY MUELLER. 

